The present invention relates to sash windows and in particular to a mounting for the spring tensioning arrangement used in such sash windows.
Modern sash window arrangements utilise flat coiled ribbon springs which are arranged to unwind as the sash is slid and moved within a window frame. The coiled springs provide a counterbalancing force to counterbalance the weight of the sash window thereby making movement, and opening of the window easier. Typically the coiled springs are mounted, via a mounting arrangement, within a vertical channel section of the window frame or jamb. A free end, referred to as a tail, of the spring is connected to a sash shoe slidably mounted within the channel section of the window frame. The shoe in turn is then connected to the sash window jamb, usually towards the lower portion of the sash window.
The coil springs are generally of a constant tension type in which the outer profile of the coil itself is rotatably held and supported within the mounting whilst the other free end of the spring is free such that the coil spring can rotate as the spring is unwound and the tail is extended. To provide sufficient force to counterbalance the weight of the sash window multiple springs may be provided with the free ends or tails connected together.
An example of a prior arrangement, as generally described above, for a mounting for multiple springs for use in a sash window is described in U.S. Pat. No. 5,365,638. As described in this prior patent, individual mounting means are provided for each of the coil springs. The spring mounting comprises two parallel arranged upstanding wall portions with a coil spring support element interconnecting these wall portions. The coil spring is inserted in between the wall portions with an outer coil surface of the spring supported and resting on the coil spring support element/surface. To provide a multiple spring assembly a number of individual mounting means are provided and stacked into an assembly in the window jamb.
Whilst this mounting arrangement, and similar prior arrangements, provide a practical method of mounting and supporting the springs, there are a number of problems with such an arrangement and the mounting arrangement can be improved generally. Particular problems are that the individual mounting for the springs are relatively complex and involve a number of different components. This increases production costs. The individual mountings also have to be installed individually and/or assembled which increases assembly time and costs. Installation of a stack of mountings within the channel section can also in practice be difficult. The installation of the sash shoe can also be problematic, in particular due to the applied tension of the springs which are attached to them. The correct lateral location of the prior mountings within the channel section and alignment of mounting can also be difficult especially due to the restricted access to the channel section. The stack of mountings secured to the jamb via a single screw fitting also have a tendency to undesirably bow under the tension of the springs. If multiple screw fasteners are used to reduce this bowing then assembly time is increased. It has also been found that dirt can accumulate within the mounting assembly and springs. This can adversely affect performance and operation of the counterbalance. The prior art mountings also obstruct the channel section within which the tilt latch is engaged to locate the sash. Consequently the prior art mountings have to be carefully positioned within the jambs such that opening of the window is not restricted.
It is therefore desirable to provide an improved sash window spring tensioning mounting arrangement which addresses some or all the above described problems and/or which offers improvements generally.
According to the present invention there is provided a sash window counterbalance spring mounting arrangement as described in the accompanying claims.
In an embodiment of the invention, which includes a number of complementary and/or separate but related aspects and features of the invention, there is provided a sash window counterbalance spring mounting arrangement for fitment into a channel section within a window jamb. The arrangement comprises at least two coiled ribbon springs, a spring support mounting comprising support means for each of said at least two coiled ribbon springs to support and locate said coiled ribbon springs to the spring support mounting, and locating means adapted, in use, to locate the spring support mounting within and to said channel section. The spring support mounting comprises a single integral component from which the support means depend and from which the at least two springs are located and supported.
A spring support mounting comprising a single integral component, ie of a one-piece format, for a multi spring counterbalance arrangement is much simpler to fabricate than the prior multi piece format conventionally used. The single integral format is also much simpler to fit into the channel section than fitting the individual support mountings for each of the multiple springs as used in the prior art arrangements. Using a single integral support mounting component also allows the multiple springs to be more closely located to each other which reduces the potential bowing of the support mounting under the spring load.
The spring support mounting comprises an elongate plate like main body portion, the main body portion having a front and rear surface. The support means comprises integral projections from a rear surface of the main body portion. Preferably at least one of the at least two springs comprise a pair of triangular cross section integral projections which extend from the rear surface of the main body portion. The triangular cross section projections are respectively disposed laterally on the rear surface with the respective triangular cross sections laterally oppositely directed such that the pair of triangular projections define a cradle for said spring.
Such triangular cross section projections provide a simple and convenient support mounting for the springs. Furthermore they also allow the springs to be located closely together which, as mentioned above, reduces the possibility and problems of bowing of the spring support mounting.
An end portion of the main body portion of the support mounting is curved in a direction extending from the rear surface of the main body such that a tip edge of the end portion of the main body is disposed at a position spaced from a plane of the remainder of the main body portion. The end portion is thereby arranged to provide a curved head portion for the spring support mounting.
Such a curved head to the spring support mounting allows a tilt latch, which engages within the channel into which the support mounting is fitted, to glide over the installed spring support mounting.
When the mounting arrangement is installed within said channel section of the window jamb, the tip edge of the curved head portion is arranged to abut against a wall of said channel section with the curved head portion closing off an end of the mounting arrangement.
The abutment of the tip edge of the curved head portion with a wall of the channel section closes off the end of the mounting arrangement and assists in keeping dirt out of the mounting arrangement and the coiled springs. In addition it also, in part, seals off the channel section so reducing drafts through the channel section.
The curved head portion is resilient and tip edge of the curved head portion is arranged to resiliently abut against said wall of the channel section such that the spring support mounting is urged away from said wall.
The resilient abutment of the curved head and tip thereof ensures that there is a good seal between the tip and curved head portion. It also provides a secure means to locate the support mounting within the channel between the walls of the channel whilst also allowing the mounting arrangement to accommodate any manufacturing tolerance variations in the channel dimensions.
Wing projections extend from the front surface of the main body of the spring support mounting. A distal end of the wing projections is arranged, when the spring mounting is installed within the channel, to abut against a wall of said channel and to space the front surface of the main body of the spring support mounting from said channel wall.
The wing projections provide a means to laterally locate the support mounting within the channel section, whilst spacing the front surface from the channel wall such that a part of the cross section of the channel section is still unobstructed by the support mounting.
On the longitudinal end of the support mounting there are inter engagement means for cooperative engagement with cooperative inter engagement features on a sash shoe. The inter engagement means preferably comprise a finger extension which is arranged to be engaged within a cooperative recess. The finger extension extends from an end of the spring support mounting, and the cooperative recess is defined in an end portion of the sash shoe.
The inter engagement means between the sash shoe and spring support mounting locate and align the sash shoe and spring support mounting such that the sash shoe and spring support mounting can be installed within the channel as a single unit. The alignment of the sash shoe with the spring support mounting also makes the installation of the shoe within the channel easier.
The support means of the spring support mounting are disposed on the spring support mounting such that in use when the at least two springs recoil rapidly an outer surface of adjacent springs contact each other.
By arranging the support means such that the springs contact when they recoil rapidly, a braking effect is provided which slows the recoiling of the springs.
An end of the spring support mounting may be provided with a buffer means for absorbing, in use, an impact of a sash shoe against said end of the spring support mounting. The buffer means may comprise coil tension springs. Alternatively the buffer means comprises a finger extension which is engaged within a recess. The finger extension and recess are profiled such that as the finger extension is inserted into the recess the finger extension and recess progressively and increasingly frictionally engage each other.
Such a buffer means reduces damage that may be caused in the event that the sash shoe impact the spring support mounting.
The spring support mounting is resiliently flexible in directions extending from the front and rear surfaces.
Such flexibility in the support mounting allows the support mounting to be bent during installation of the support mounting within the channel section. This allows the support mounting comprising an elongate single integral component to be inserted through an industry standard channel opening which is shorter in length than the support mounting.